﻿#region Copyright and Licensing Notice
// Copyright (C) 2011 Steven Bosnick
// 
// This program is open source software; you can redistribute it 
// and/or modifiy it under the terms of the Eclipse Public License,
// version 1.0.
// 
// This program is distributed in the hope that it will be useful, 
// but WITHOUT ANY WARRANTY; without even the implied
// warranty of MERCHANTABILITY or FITNESS FOR A 
// PARTICULAR PURPOSE. See the Eclipse Public License for more
// details.
// 
// You should have received a copy of the Eclipse Public License 
// along with this program; if not, you can find a copy at
// "http://www.opensource.org/licenses/eclipse-1.0.php".
#endregion
using System;
using BitwiseOre.SharedMemory.Core.Common;

namespace BitwiseOre.SharedMemory.Core.Threading
{
    internal sealed class TimeoutHelper : ITimeoutHelper
    {
        private readonly IClock _clock;
        private readonly DateTime _deadline;

        public TimeoutHelper(TimeSpan timeout, IClock clock)
        {
            if (timeout < TimeSpan.Zero) throw new ArgumentOutOfRangeException("timeout");
            
            _clock = clock;
            _deadline = _clock.Now + timeout;
        }

        public TimeSpan RemainingTime
        {
            get
            {
                var remainingtime = _deadline - _clock.Now;
                return remainingtime >= TimeSpan.Zero
                           ? remainingtime
                           : TimeSpan.Zero;
            }
        }
    }
}